A watchdog timer (WDT) is a piece of hardware that performs a controlled system restart when an electronic system has failed due to an unexpected software or system delay. The WDT works by generating a system reset when a pre-defined time period has elapsed. In operation, an application software has to reset the WDT's counter within the pre-defined time period to avoid the system reset.
A conventional watchdog timer only detects a “too-late” system response—that is, when an amount of time has passed during which an instruction should have been executed, but it was not. The inventor hereof has recognized, however, that an application software may get stuck within a loop where a restart of the watchdog timer is implemented. In those cases, a conventional watchdog timer is not capable of detecting the error because the restarting of the loop resets the WDT every time. Moreover, a conventional WDT cannot detect certain types of clock failures.
To address these, and other shortcomings, the inventor hereof has developed the various systems and methods for a dual window watchdog timer (DWWDT) that are particularly useful, for example, in automotive applications.